FIG. 10 shows an example of a card edge connector 101 that is connected to a card C or other object of connection according to the prior art (see JP6-31088U). As shown in FIG. 10, the card edge connector 101 comprises an insulating housing 110 having a card receiving groove 111 that extends in a direction of length. A plurality of first contacts 120 and second contacts 120′ are attached to the housing 110. Each of the first contacts 120 comprises a substantially rectangular base member 121, an attachment leg 122 that extends forward (rightward in FIG. 10) from the base member 121, a board connecting member 123 that extends from a lower edge of the base member 121, and a contact arm 125 that extends from an upper edge of the base member 121. Each of the contact arms 125 extends via a bent member 124 that extends forward from the upper edge of the base member 121 in a bent manner. From the bent member 124, each of the contact arms 125 first extends forward obliquely upward and then extends further forward while gradually inclining downward. A contact projection 126 that contacts a conductor pad (not shown) provided on an upper surface of the card C is provided at a front end of each of the contact arms 125. Each of the attachment legs 122 is designed to be press-fitted to a corresponding attachment opening 112 formed in the housing 110. Each of the board connecting members 123 is designed to be connected by soldering to a conductor pad provided on a circuit board PCB. Each of the first contacts 120 is formed by stamping a conductive metal plate.
Each of the second contacts 120′ comprises a substantially rectangular base member 121′, an attachment leg 122′ that extends forward from the base member 121′, a board connecting member 123′ that extends from a lower edge of the base member 121′, and a contact arm 125′ that extends from an upper edge of the base member 121′. Each of the contact arms 125′ extends via a bent member 124′ that extends forward from the upper edge of the base member 121′ in a bent manner. From the bent member 124′, each of the contact arms 125′ first extends forward obliquely downward and then extends further forward while gradually inclining upward. A contact projection 126′ that contacts a conductor pad (not shown) provided on a lower surface of the card C is provided at a front end of each of the contact arms 125′. Each of the attachment legs 122′ is designed to be press-fitted to the corresponding attachment opening 112 formed in the housing 110. Each of the board connecting members 123′ is designed to be connected by soldering to a conductor pad provided on the circuit board PCB. Each of the second contacts 120′ is formed by stamping a conductive metal plate.
The first and second contacts 120, 120′ are alternately disposed in a contact arrangement direction (direction of length of the receiving groove 111) and are designed so that the contact arms 125 and contact arms 125′ do not overlap with each other, as shown in FIG. 10. By alternately disposing the first and second contacts 120, 120′ in the contact arrangement direction, the first contacts 120 having the contact arms 125 contact the upper surface of the card C and the second contacts 120′ having the contact arms 125′ contact the lower surface of the card C. Stress applied to the housing 110 that holds the attachment legs 122, 122′ is therefore dispersed, so that damage to the housing 110 and cracking in the soldered portions of the board connecting members 123, 123′ can also be prevented.
In the card edge connector 101 shown in FIG. 10, the first and second contacts 120, 120′ that are disposed in the contact arrangement direction are devised so that the contact arms 125 and the contact arms 125′ do not overlap with each other as seen in FIG. 10. The areas of the first and second contacts 120, 120′ other than the first and contact arms 125, 125′, however, do overlap with each other. Accordingly, capacitive coupling occurs between adjacent first and second contacts 120, 120′, so that impedance becomes small. For example, in cases where the contact pitch between adjacent first and second contacts 120, 120′ is as small as 0.6 mm. It is therefore difficult to adjust the impedance to a specified value such as 100 Ω.
FIGS. 11A-11B show an example of a high-density connector 201 according to the prior art (see JP5-159831A). Although the high-density connector 201 is a different type of connector than the card edge connector 101 shown in FIG. 10, the high-density connector 201 reduces the capacitance produced between adjacent terminals by reducing opposing areas of adjacent terminals, thus reducing crosstalk between the adjacent terminals.
As shown in FIG. 11B, the high-density connector 201 comprises an insulating housing 210 provided with terminal accommodating openings 211 formed in a plurality of rows. A plurality of first and second terminals 220, 221 is accommodated inside the terminal accommodating openings 211. Ground plates 223 are provided on an outer circumference of the housing 210 and between the rows of the first and second terminals 220, 221. The ground plates 223 provided on the outer circumference of the housing 210 are not shown in the figures.
As shown in FIG. 11A, each of the first terminals 220 comprises a straight body member 220a that extends in a vertical direction and has a sectional U shape, a connecting member 220b that is formed by being extended outward from a lower edge of a back wall of the straight body member 220a and then bent downward, and a pair of contact members 220c that respectively extend in an opposing manner from upper edges of opposing side walls of the straight body member 220a. A plurality of corner openings 220d are formed at both corner edges (where the opposing side walls and the back wall of each of the straight body members 220a contact with each other) at a specified interval along the vertical direction. Each of the first terminals 220 is formed by stamping and forming a metal plate.
Each of the second terminals 221 comprises a straight body member 221a that extends in the vertical direction and that has a sectional U shape, a connecting member 221b that is formed by being extended inward from a lower edge of a back wall of the straight body member 221a and then bent downward, and a pair of contact members 221c that respectively extend in an opposing manner from the upper edges of the opposing side walls of the straight body member 221a. A plurality of corner openings 221d formed at both corner edges of each of the straight body members 221a at a specified interval along the vertical direction. Each of the second terminals 221 is formed by stamping and forming a metal plate.
The first terminals 220 and second terminals 221 are alternately disposed in the contact arrangement direction so that the opposing side walls overlap, as shown in FIG. 11B. The opposing areas of the adjacent first and second terminals 220, 221 can be reduced by appropriately setting the size of the corner openings 220d, 221d that are formed in the first and second terminals 220, 221. Accordingly, the capacitance produced between the adjacent first and second terminals 220, 221 can be reduced. As a result, crosstalk between the adjacent terminals first and second terminals 220, 221 can be reduced.
In the high-density connector 201 shown in FIGS. 11A-11B, although it is possible to reduce the capacitance produced between adjacent first and second terminals 220, 221 by reducing the opposing areas of adjacent first and second terminals 220, 221, the first and second terminals 220, 221 have straight base members 220a, 221a that each having a sectional U shape. The first and second terminals 220, 221 are therefore large, which makes the making first and second terminals 220, 221 unsuitable for use in a compact, low-profile connector.